Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties
Thesis (PhD)--University of Pretoria, 2019.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2020
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613701074321408 |
|---|---|
| access_status_str | Open Access |
| author2 | Siyasiya, Charles Witness |
| author_browse | Siyasiya, Charles Witness |
| author_facet | Siyasiya, Charles Witness |
| collection | Thesis |
| dc_rights_str_mv | © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2019. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/77843 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:19.405Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/77843 The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties Siyasiya, Charles Witness u26362181@tuks.co.za Mostert, R.J. (Roelf) Bolokang, A.S. Mathabathe, Maria Ntsoaki UCTD Microstructure evolution Intermetallic alloys Mechanical properties Bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped Titanium Aluminide Alloys (TiAl) Bulk Alloy Development Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action Thesis (PhD)--University of Pretoria, 2019. The -TiAl based intermetallic alloys play an important role in structural applications, such as aerospace and automotive industries. The current work studied the novel development and microstructural evolution, along with their mechanical properties of the -TiAl based alloys viz. the binary (Ti--48Al), ternary (Ti--48Al-2Nb), quaternary (Ti--48Al-2Nb-0.7Cr) and quinary (Ti- -48Al-2Nb-0.7Cr-0.3Si). The alloys were fabricated employing both powder and ingot metallurgy routes. Consolidation of the alloys was achieved by vacuum arc melting. As-cast and thermally treated sections of sample ingots were characterized using optical microscopy (OM) and scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photo-electron spectroscopy (XPS), atomic force microscopy (AFM), Raman spectroscopy (RS), transmission electron microscopy (TEM), electron backscattered diffraction (EBSD). Thermal analysis, such as differential scanning calorimetry (DSC) and differential thermal analysis (DTA) were employed in order to give insight into phase transformations. Moreover, hardness, room temperature tensile testing with subsequent fractography, cyclic oxidation, nitriding treatment and incorporating first principle calculations with orientation relationships were some of the property behaviors studied in the dissertation. The key findings of the research were: 1) the addition of Nb and Cr to the -TiAl based alloys promoted grain refinement and induced phase transformation, 2) slight overall Al loss of the -TiAl based alloys was observed due to the compaction method prior to melting. Uni-axial cold pressing of the blended metal powders indicated that Al particles migrated to the surface in contact with the die facets, 3) of all the alloys studied, the quinary (Ti-48Al-2Nb-0.7Cr-0.3Si) alloy exhibited good mechanical properties, 4) phase transformation and microstructural evolution of an α-solidifying quinary alloy illustrated a homogeneous microstructure with Spheriodized/Widmanstätten laths, 5) it has been shown that the formation of /α2/Ti5Si3 in the Ti-48Al-2Nb-0.7Cr-0.3Si intermetallic alloy followed the Blackburn orientation relationship of both the as-cast (-solidifying) and heat-treated (α-solidifying) phases, 6) surface cladding in a N/Ar atmosphere indicated that the oxidation properties of the ternary and quinary showed improved significance compared to the binary and quaternary alloys and, 7) Sn and Mn, were some of the doping elements added to the quinary alloy excluding the Cr due to its inducement of the brittle β-phase which exhibits low mechanical properties. As a result, -TiAl based Ti- 48Al-2Nb-0.3Si, Ti-48Al-2Nb-1Sn-0.3Si, and Ti-48Al-2Nb-1Sn-0.7Mn-0.3Si intermetallic alloys were developed and investigated. mi2025 Materials Science and Metallurgical Engineering PhD Unrestricted SDG-04: Quality education SDG-07: Affordable and clean energy SDG-08: Decent work and economic growth SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production SDG-13: Climate action 2020-12-29T11:50:53Z 2020-12-29T11:50:53Z 2020/04/29 2019 Thesis Mathabathe, MN 2019, The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/77843> A2020 http://hdl.handle.net/2263/77843 en © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Microstructure evolution Intermetallic alloys Mechanical properties Bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped Titanium Aluminide Alloys (TiAl) Bulk Alloy Development Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties |
| title | The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties |
| title_full | The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties |
| title_fullStr | The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties |
| title_full_unstemmed | The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties |
| title_short | The development and microstructural evolution of the bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped intermetallic alloys and their mechanical properties |
| title_sort | development and microstructural evolution of the bulk yti 45al 2nb sn cr mn amp si doped intermetallic alloys and their mechanical properties |
| topic | UCTD Microstructure evolution Intermetallic alloys Mechanical properties Bulk yTi-45Al-2Nb (Sn Cr Mn & Si)-doped Titanium Aluminide Alloys (TiAl) Bulk Alloy Development Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action |
| url | http://hdl.handle.net/2263/77843 |